iMechanica - ABAQUS shell element stress output - Comments

It worked, thank you so much

PJtree23 — Sat, 01 Nov 2008 19:18:58 -0400

It worked, thank you so much Biswajit!

For my simulation I was running into errors with the S4R element however, in the example you posted the S3R element was used. I am now using the S3R element for all of my models with good success. I was curious about why this worked.

Could it be that the SR4 element is numerically "less sophisticated" than the SR3 element for curved surface modeling? Just a thought.

Anyway, another question about interpreting the von Mises stress plots, for the position selection I am selecting "Unique Nodal" and the graph contains two sets of data :

S, Mises (Avg: 75%) SP:1 PR:SHELLCBAV_SM-1 N:16_1

S, Mises (Avg: 75%) SP:5 PR:SHELLCBAV_SM-1 N:16_1

What do the terms SP:1 and SP:5 correspond to? (in bold)

Are they the outer and inner surfaces of the shell element?

Thanks,

Re: impossible for ABAQUS to report the stress or strains ...

Biswajit Banerjee — Thu, 23 Oct 2008 01:06:17 -0400

".. guess it is impossible for ABAQUS to report the stress or strains of a shell element".

I took that as a challenge and decided to pursue the matter. I don't use ABAQUS at present nor have I used it extensively in the past.

If searched the web an found an Abaqus manual at http://www.hlrs.de/v6.6/books/exa/default.htm. After reading TFM I found an example at http://www.hlrs.de/v6.6/books/eif/pressfueltank_uniformthick.inp

There I saw the following string of commands

*NODE PRINT,FREQUENCY=0
*EL PRINT,FREQUENCY=0
*EL FILE,ELSET=SAMPLE
STH,
SINV,
*OUTPUT,FIELD,VAR=PRESELECT,FREQ=10
*ELEMENT OUTPUT
STH,
*OUTPUT,FIELD
*ELEMENT OUTPUT,ELSET=SAMPLE
STH,
SINV,
*OUTPUT,HISTORY
*ELEMENT OUTPUT,ELSET=SAMPLE
STH,
SINV,

Then I tracked down the Abaqus keywords manual (at http://www.hlrs.de/v6.6/books/key/default.htm) and searched TFM for *element output. The help page said that this command determined which variables were to be saved. A little more of searching pointed out that STH means section thickness and SINV means stress invariants.

I presume that if you save these quantities you should be able to plot the von Mises stresses. The exercise took me less than 15 minutes.

-- Biswajit

So nobody knows the

PJtree23 — Wed, 22 Oct 2008 11:15:43 -0400

So nobody knows the answer? I am guess it is impossible for ABAQUS to report the stress or strains of a shell element....can anyone please tell me what is going on here?

ABAQUS shell element stress output

PJtree23 — Mon, 06 Oct 2008 12:05:23 -0400

Hello,

I am running ABAQUS EXPLICIT to simulate aortic valve function. I created a model using hex shell elements. When the simulation is complete the output contours are in U,Magnitude, in the list of primary variables to show; there are a few other options, put they are all of kinematic/dynamic nature, there are no options for material stresses or strains.

I realize that U,Magnitude is displacment, but how can I visualize the von mises stress contours? Von mises stress is selected in the Field Output criterium. I am completely out of ideas and very frustrated, please make comments or let me know where to look for a solution, please!

Thanks in advance,